I have posted my effort of an Australian Catalogue for our sliding windows.
Like SFS, SFS over FFF or a number of others that we use commonly.
It's based on Stegbar's catalogue (now have a connection with JeldWen.
I have used Window Objects rather than DWA's so that I can put it the std window sizes (to aussie brick sizes). There is also a bunch of DWA's as well.
Like any WO they can stretch to any shape but there will be some distortion in the frames as they stretch too far.
It's a WIP but it may show an option for creation of your frames.
My blog has a fuller article and link
http://ausaca.blogspot.com/2008/10/window-frames.html